Vibration damping devices, for example provided as multistage torsion vibration dampers, are known in the art in many embodiments. When disposed in a drive train, they function, viewed in the direction of the force flow, as an elastic clutch between an input and an output and are coupled to the connection elements forming the input and the output. The device transfers torque and simultaneously compensates vibrations occurring during power transmission. Also, an embodiment as an absorber is conceivable. In this case, the device does not transfer any torque between the adjacent connection elements, but only torque spikes are reduced through the particular components. Such vibration damping devices are based on different functional principles depending on the type of damping. Besides purely mechanical damping solutions also hydraulic damping solutions and combined mechanical-hydraulic damping solutions are known. Mechanical dampers include a rotating component which can have one or several components and which functions as an input component or output component of the vibration damper depending on the direction of the force flow, particularly a primary component and a secondary component which are disposed coaxial to one other and which are rotatable within limits in circumferential direction relative to one another. The coupling between the input component and the output component is performed through torque transfer devices and vibration damping devices which are typically formed by spring units and which include at least one spring element provided as a compression spring. Vibrations can be compensated and reduced through the size of the relative rotation angle between the input component and the output component and the spring force.
From the printed document DE 30 47 039 A1 an embodiment of a device of this type for damping vibrations and for transmitting torque between an input and an output is known which includes two damper assemblies connected in series. In order to facilitate a larger relative movement between the driving and driven elements of the vibration damper, the device is provided with two stages. Thus, the device includes two concentric circles of damping springs which are configured in a housing and which are driven by drive lugs which are mounted in a drive element, e.g. a piston plate for a lock up clutch. Thus, floating elements separate the springs in the inner and outer spring circles into two or more groups of springs. Thus, the two or more groups of springs function in parallel to one another in each circle, while the springs in each group function in series. Thus, the power transfer in the force flow is performed in series. The output component formed by side disks of the first radially outer damper assembly is connected torque proof to the input component of the second damper assembly. Thus, the configuration of the device is very complex and requires a large amount of installation space.
Another embodiment of a series damper for use in force transmission devices with a hydrodynamic component, like e.g. a hydrodynamic torque converter or a hydrodynamic clutch or a lockup clutch, is known from the printed document DE 199 20 542 A1. The vibration damper can thus be connected in series to the hydrodynamic component and also to the lockup clutch, or it can only be connected in series with the lockup clutch. The vibration damping device is configured at least as a two-stage series damper including a primary damping stage and a pre-damping stage. The damper assembly of the pre-damping stage is disposed radially on the larger diameter than the damper assembly of the primary damping stage, which is particularly offset in radial direction in direction towards the direction of rotation. The particular embodiments with pre-damper assembly and primary damper assembly are characterized by an axial offset viewed in installed position. Furthermore, the relative rotation angle of the damper assembly is mostly limited for the primary damper stage due to the small diameter of the reference circle.
From the printed documents U.S. Patent Application No. 2004/0216979 A1 and U.S. Patent Application No. 2004/0185940, embodiments of parallel dampers are known. From the printed document U.S. Patent Application No. 2004/0216979 A1 an embodiment of a vibration damper is known including at least two damper assemblies which are connected in parallel. Both damper assemblies are effective continuously. The damper assembly for the smaller rotation angles is disposed on a radially inner diameter, while the greater rotation clearance is implemented through the second damper assembly on a radially outer diameter. The radially inner damper assembly is configured as a series damper, including spring elements separated by a single component flange and connected in series.
From the printed document U.S. Patent Application No. 2004/0185940 a vibration damping device is known which is configured as a series—parallel damper including a first rotating element and a second rotating element which are rotatable relative to one another within limits. Furthermore, the device includes a pair of first elastic elements oriented in one rotation direction and connected in series, which are coupled through a floating intermediary flange and another second elastic element, which is connected in parallel to the first elastic elements. The second elastic element is configured, so that it is compressed in the rotation direction after the pair of first elastic elements is compressed to a first angle due to a relative rotation of the first rotating element and the second rotating element. For this purpose a free angle is associated with the second elastic element, which free angle in integrated in the rotating flange. The disposition of first and second elastic elements is provided overlapping for reducing the radial installation space to one diameter or in radial direction with respect to the annular portions theoretically created through the extension of the spring elements. The coupling between the first elastic elements is performed through a floating flange.
All cited embodiments have in common that the spring characteristic is adapted with respect to a desired property in a particular operating range.